Good Evening ,

I will be poting the link  to the full report done by Multiple agencies on the Derecho of June 29 2012

I will pull some important info out on this blog ,

Full Report NWS

On June 29, 2012, a devastating line of thunderstorms known as a derecho (deh REY cho) moved east-southeast at 60 miles per hour (mph) from Indiana in the early afternoon to the Mid-Atlantic region around midnight. The states most significantly impacted were Indiana, Ohio, Kentucky, Pennsylvania, West Virginia, Maryland, Virginia, Delaware, New Jersey, and North Carolina, as well as Washington, D.C. Nearly every county impacted by this convective system suffered damages and power outages. Winds were commonly above 60 mph with numerous reports of winds exceeding 80 mph. Some areas reported isolated pockets of winds greater than 100 mph. The storm resulted in 13 deaths, mainly a result of falling trees. One major impact from the derecho was widespread power outages. More than 4 million customers were without power, some for more than a week after the storms moved through. To make matters worse, the area affected was in the midst of a prolonged heat wave. There were 34 heat-related fatalities in areas without power because of the derecho.

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2. Derecho Science and Climatology
A derecho is a complex of thunderstorms or a mesoscale convective system (MCS) that produces large swaths of severe, straight-line wind damage at Earth’s surface. Johns and Hirt (1987) set spatial, temporal, and damage limitations when classifying thunderstorm complexes as derechos. Specifically, for an MCS to be classified as a derecho, the following conditions must be met:
• There must be a concentrated area of convectively induced wind damage or gusts greater than or equal to 58 mph occurring over a path length of at least 250 miles.
• Wind reports must show a pattern of chronological progression in either a singular swath (progressive; this event was a classic example) or a series of swaths (serial).
• There must be at least three reports separated by 64 kilometers (km) or more of Enhanced Fujita 1 (EF1 damage) and/or measured convective wind gusts of 74 mph or greater.
• No more than 3 hours can elapse between successive wind damage/gust events.
Derechos occur year-round but are most common from May to August (Coniglio et al., 2004). Derechos form in a wide spectrum of large-scale weather patterns and occur in a broad range of air mass instability and low to mid-level wind shear (the change of wind direction and speed with height) environments (Evans and Doswell, 2001). The majority of events fall into three jet stream patterns:
• Well-defined approaching upper level disturbance
• Upper-level ridge of high pressure
• Zonal west to east flow
In the last two patterns particularly, the forcing for the development of a derecho can be subtle and difficult to forecast. Forecasters may be aware that a pattern is setting up for a potential derecho, but pinpointing the timing and location of the storms is often problematic because favorable patterns may exist for several days without derecho formation.
For progressive derechos, like this event, a west-to-east oriented surface frontal boundary usually exists. The derecho typically initiates on the north side of the boundary as loosely organized elevated thunderstorms, which eventually grow upscale, forming a large bow shaped echo. The bow echo then moves east-southeastward crossing the front into the warm and very unstable air to the south (Johns, 1993). The storm-scale mechanisms governing the upscale growth and the transition from elevated to surface-based storms are not well understood. The demise of derechos tends to occur when they move into an environment of weaker instability and low to mid-level wind shear (Coniglio et al., 2004).
Coniglio and Stensrud (2004) developed a climatology of derechos for the eastern half of the United States. Figure 1 displays this derecho climatology for May through August from 1980-2001.

LOSS OF WEATHER RADIOS

Transmitter
Date of Outage
Date Restored
Reason for Outage
Manassas, VA
June 29, 2012
July 04, 2012
No power or phone lines to site
Baltimore, MD
June 29, 2012
July 02, 2012
No power or phone lines to site
Hagerstown, MD
June 29, 2012
July 02, 2012
No power or phone lines to site
Frostburg, MD
June 29, 2012
July 01, 2012
No power or phone lines to site
Fredericksburg, VA
June 29, 2012
July 03, 2012
No power or phone lines to site
Washington, D.C.
June 29, 2012
July 04, 2012
No power or phone lines to site
Moorefield, WV
June 29, 2012
July 02, 2012
No power or phone lines to site
Charlottesville, VA
June 29, 2012
June 30, 2012
No power or phone lines to site

Table 2: Power outage data by state provided by FEMA
State
Number of customers without Power on July 05, 2012
Number of customers without power at peak of outage
New Jersey
17,564
135,322
Washington, D.C.
1,000
68,567
Maryland
53,442
899,171
Virginia
89,104
1,076,051
Kentucky
1,000
52,616
Indiana
3,900
135,177
Ohio
139,080
915,366
West Virginia
226,483
643,284

I will be Adding to this

Dean D Davison

Storm Surge LLC

Lead Forecaster